This invention relates generally to clothes washing machines and the like devices which execute a centrifugal extraction cycle and more particularly to an improved out-of-balance and safety switch arrangement for such devices.
It is not uncommon in washing machines which include a centrifugal extraction cycle to exhibit a tendency to gyrate or vibrate excessively when the articles of clothing being centrifuged accumulate in one area of the washer tub or basket, thus unbalancing the tub. If this should occur, the out-of-balance rotating tub may strike and possibly damage the surrounding structure of the machine. To prevent the latter from occurring, switch arrangements which open the circuit to the tub drive motor in response to excessive unbalanced rotation of the tub have been provided. Many of these switch arrangements have been combined with a cover actuated switch which also opens the circuit upon opening the access cover to the washing machine tub and closing the circuit upon closing the tub access cover.
Examples of such switch arrangements are shown in U.S. Pat. Nos. 3,145,818; 3,227,835; and 3,504,777. While it appears that the switch arrangements of the last-mentioned patents will operate satisfactorily to prevent damage to a washing machine in the case of excessive gyration of the clothes tub as well as deactivate the washer drive motor to prevent injury to an operator opening the tub access cover during the operation of the washer, these arrangements appear for the most part to be rather complicated in design and as such would most likely be expensive to manufacture.
More specifically, the arrangement of the U.S. Pat. No. 3,145,818 employs tension and compression springs and a dual actuated switch to interrupt and complete the circuit to the washer drive motor. Furthermore, the arrangement requires a rubber or the like resilient knob mounted in an inner wall of the washer adjacent the tub for engagement by the tub when it is out of balance, to trigger certain linkages for deactivating the switch.
The construction of the arrangement of the U.S. Pat. No. 3,227,835 is also complicated, requiring a sliding plunger and a releasable catch mechanism which interact to provide the desired result.
The arrangement of the U.S. Pat. No. 3,504,777 also includes a large number of components, having a pair of springs which are stressed to move a latch and switch mechanism between two operating positions.
In addition to being costly and difficult to manufacture, it appears that there may be a tendency for the arrangements of the above-mentioned patents to become inoperative after a period of use because of the many interacting components employed therein.